Change bath taps (like-for-like or to mixer)
- Robert Costart
- May 29
- 3 min read
Updated: Jun 4
š Overview
Replacing existing bath pillar taps or upgrading to a single-lever mixer, including disconnecting supplies, fitting the new tap(s) and testing for leaks.
Skill level: 3 / 5Ā (competent DIYer with basic plumbing confidence)
Typical duration: 2ā3 hĀ hands-on
ā ļø Safety First
Isolate hot and cold supplies fully before loosening any fittings to prevent flooding and scalding.
Open the bath taps to depressurise the pipework and avoid spray-back.
Sharp edges on old chromeware and confined working spaces can cause cutsāwear cut-resistant gloves.
Use eye protection when cutting or deburring pipe; copper shards fly unpredictably.
Keep electrical items well clear of the bath to avoid shock hazards while you work with water.
š§° Tools & Materials
Item | Purpose |
|---|---|
Adjustable spanner & basin wrench | Loosen tap-back nuts in tight spots |
Box spanner (27 mm/32 mm) | Reaches deep-seated back-nuts on many UK baths |
Flat & Phillips screwdrivers | Remove handles/escutcheons if needed. |
PTFE tape | Seal compression or threaded joints |
Compression olives & nuts / flexi tap tails | Connect the new tap to the supply pipework. |
Pipe cutter & deburr tool | Shorten/clean copper pipe ends for mixer installation. |
Plumberās silicone grease | Ease rubber seals; prolong O-rings |
Non-setting sanitary silicone | Seal the mixer base to the bath top. |
Bucket, towels & old clothes | Catch residual water and protect enamel |
Torch and kneeling pad | Improve visibility & comfort under the bath. |
š Step-by-Step to changing bath taps
1. Isolate and drain
Action: Close service valves (or main stopcock) and open both bath taps to drain.
Why: Removes pressure so fittings can be undone safely.
Pro-tip: If no isolation valves exist, consider adding full-bore lever valves on each supply before re-assembly for future convenience.
2. Access the tap tails
Action: Remove the bath side panel or reach in through the service hatch.
Why: Provides room for tools and visual checks.
Pro-tip: Photograph the existing pipework; a quick reference beats memory when re-routing for a mixer.
3. Loosen supply connectors
Action: Hold the tap tail with a spanner while undoing each compression nut or flexi tail.
Why: Prevents twisting and stressing the copper pipe.
Pro-tip: Have a small bucket readyāthereās always a last dribble.
4. Remove the old taps
Action: From beneath, undo the brass back-nut using a box/basin wrench, then lift the tap out.
Why: Frees the fitting without gouging the bath enamel above.
Pro-tip: If the back-nut is seized, spray penetrating oil and tap the wrench gently to shock it looseāavoid flames near plastic waste pipes.
5. Prepare the seating
Action: Scrape away old sealant and limescale with a plastic scraper; wipe with methylated spirits.
Why: A clean, flat surface ensures the new tap gasket seals first time.
6. Fit the new tap(s)
Action: Insert the new tap(s) with supplied rubber/foam gasket; hand-tighten the back-nut from beneath.
Why: Centres the tap accurately in the hole and compresses the seal.
Pro-tip: Smear a film of plumberās silicone grease on the gasket to ease future removal and resist limescale.
7. Connect the water supplies
Like-for-like pillars:
Action: Re-attach existing compression fittings; add fresh olives if marked.
Why: Old olives can leak once disturbed
Upgrading to a mixer:
Action: Measure tail spacing (usually 180 mm). Cut and deburr copper pipes; fit flexi tap tails or offset connectors as supplied.
Why: Mixers often need flexible tails to accommodate slight mis-alignments.
Pro-tip: Wrap two to three turns of PTFE on male threads onlyāany more can cause cracking.
8. Secure and align
Action: Final-tighten back-nuts while ensuring the tap(s) sit square and the mixer spout points centrally.
Why: Prevents movement that could strain pipe joints later.
9. Seal the rim
Action: Run a thin bead of non-setting sanitary silicone around the base where metal meets enamel; smooth with a wet finger.
Why: Stops capillary water tracking under the tap and discolouring the bath edge.
10. Re-pressurise and test
Action: Open isolation valves slowly, then run hot and cold for 30 s each. Check all joints with tissue for moisture.
Why: Tissue reveals tiny weeps before they become drips.
Pro-tip: Leave the panel off overnight; a quick glance next morning confirms no sneaky leaks.
š Completion Checks
Tap(s) sit firmly without wobble or gaps around the base.
Hot to left, cold to right (or clearly marked) and correct flow direction on mixer.
No drips or damp tissue at any joint after 10 minutesā full-flow testing.
Smooth handle action and even temperature blend on mixer.
š·āāļø When to call a pro instead
If the supply pipes are corroded or embedded in masonry, the bath has no service access, or you plan to reposition pipework significantly (e.g. switching from centre to end fill), a qualified plumber with soldering and pressure-testing gear can save timeāand potential water damage.